(VAR x y )
(STRATEGY INNERMOST)
(RULES 
        cond(true,x,y) -> cond(gr(x,y),p(x),y)
        gr(0,x) -> false
        gr(s(x),0) -> true
        gr(s(x),s(y)) -> gr(x,y)
        p(0) -> 0
        p(s(x)) -> x
        
)